JP2010052656A - Vehicular steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular steering device capable of accurately determining existence of abnormality of a signal regarding a steering angle of the vehicle. <P>SOLUTION: The vehicular steering device 8 includes: a steering angle detection means 9 for detecting the steering angle based on the signal produced so as to correspond to a rotation angle of the steering shaft 2 and outputting a steering angle signal Θs; an abnormality monitoring means for controlling an electric power steering for detecting existence of abnormality of an operation means for controlling an electric power steering; and a steering angle operation means provided with function for operating a first steering angle based on the steering angle signal Θs and operating a second steering angle based on a motor rotation angle signal Θm and determining that the first steering angle is abnormal when non-existence of abnormality of the operation means for controlling the electric power steering is detected by the abnormality monitoring means for controlling the electric power steering and deviation between the first steering angle and the second steering angle is larger than a predetermined value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle steering apparatus that includes an electric power steering apparatus and can detect an abnormality in a steering angle signal.

  In a vehicle skid prevention device, an electric power steering device, or the like, a steering angle that detects a steering angle (also referred to as a steering wheel angle or a steering angle) indicating a rotation angle of the steering of a vehicle or a steering shaft. A sensor is used. For example, in the case of a vehicle skid prevention device, the driver's steering state is calculated from the steering angle, and the braking force of each wheel of the vehicle is controlled so that the vehicle behavior according to the calculated steering angle is obtained.

  Thus, the steering angle of the vehicle plays a very important role in controlling the vehicle behavior, and there is a possibility that normal vehicle control cannot be performed if a signal related to the steering angle is abnormal. is there. For this reason, a device for detecting an abnormality of a signal related to the steering angle has been proposed.

  For example, Patent Document 1 discloses a steering angle abnormality detection device that includes a plurality of sensors that detect a steering angle and that makes the steering angle abnormal when the deviation of the output of each sensor exceeds a predetermined value. Has been. Further, in Patent Document 2, by comparing a steering angle sensor, a motor relative rotation angle obtained from a motor rotation angle sensor constituted by a resolver or the like, and an estimated steering angle estimated from an induced voltage of the motor, An electric power steering apparatus for determining an abnormality in steering angle is disclosed.

Japanese Patent Laid-Open No. 2002-104211 JP 2007-261548 A

  However, in the case of the conventional device disclosed in Patent Document 1, since the abnormality of the steering angle signal is detected based on the deviation of the steering angle signal detected by each sensor, the steering angle sensor is abnormal. However, there is a problem that it is unclear whether the steering angle calculated by the electric power steering device or the like is abnormal. Further, in the case of the conventional apparatus disclosed in Patent Document 2, in order to determine an abnormality in the steering angle in a microcomputer (hereinafter referred to as CPU) that executes control processing of the electric power steering apparatus, When the CPU fails, there is a problem that a steering angle signal cannot be obtained.

  An object of the present invention is to provide a vehicle steering apparatus that solves the problems in the conventional apparatus as described above and can accurately determine the presence or absence of a signal abnormality related to the steering angle of the vehicle.

A vehicle steering apparatus according to the present invention includes:
Steering torque detection means for detecting the steering torque based on a signal generated in response to the steering torque applied to the steering shaft of the vehicle by the driver and outputting a steering torque signal;
Motor rotation angle detecting means for detecting a motor rotation angle based on a signal generated corresponding to a rotation angle of an assist motor for applying assist torque to the steering shaft and outputting a motor rotation angle signal;
Vehicle speed detection means for detecting a vehicle speed based on a signal generated corresponding to the vehicle speed of the vehicle and outputting a vehicle speed signal;
Electric power steering control calculating means for calculating an assist command value based on at least the motor rotation angle signal, the steering torque signal, and the vehicle speed signal;
Motor driving means for driving the assist motor based on the assist command value;
Steering angle detection means for detecting a steering angle based on a signal generated corresponding to the rotation angle of the steering shaft and outputting a steering angle signal;
Electric power steering control abnormality monitoring means for detecting the presence or absence of abnormality of the electric power steering control computing means;
A function of calculating a first steering angle based on the steering angle signal and calculating a second steering angle based on the motor rotation angle signal; and for detecting the electric power steering control by the electric power steering control abnormality monitoring means. Steering angle for determining that the first steering angle is abnormal when no abnormality is detected in the computing means and the deviation between the first steering angle and the second steering angle is greater than a predetermined value And an arithmetic means.

  In the vehicle steering apparatus according to the present invention, preferably, the electric power steering control abnormality monitoring means detects that the electric power steering control calculating means is not abnormal, and the first steering angle, the second steering angle, Is less than the predetermined value, or when the abnormality of the electric power steering control calculation means is detected by the electric power steering control abnormality monitoring means, the first steering angle of the vehicle is Steering angle.

  Furthermore, in the vehicle steering apparatus according to the present invention, preferably, the electric power steering control abnormality monitoring means detects that the electric power steering control calculating means is not abnormal, and the first steering angle and the second steering are detected. When the deviation from the angle is larger than the predetermined value, the second steering angle is set as the steering angle of the vehicle.

The vehicle steering apparatus according to the present invention includes steering torque detection means for detecting a steering torque based on a signal generated in response to a steering torque applied to a steering shaft of the vehicle by a driver and outputting a steering torque signal. ,
Motor rotation angle detecting means for detecting a motor rotation angle based on a signal generated corresponding to a rotation angle of an assist motor for applying assist torque to the steering shaft and outputting a motor rotation angle signal;
Vehicle speed detection means for detecting a vehicle speed based on a signal generated corresponding to the vehicle speed of the vehicle and outputting a vehicle speed signal;
Electric power steering control calculating means for calculating an assist command value based on at least the motor rotation angle signal, the steering torque signal, and the vehicle speed signal;
Motor driving means for driving the assist motor based on the assist command value;
Steering angle detection means for detecting a steering angle based on a signal generated corresponding to the rotation angle of the steering shaft and outputting a steering angle signal;
Yaw rate detection means for detecting a yaw rate based on a signal corresponding to the yaw rate of the vehicle and outputting a yaw rate signal;
Electric power steering control abnormality monitoring means for detecting the presence or absence of abnormality of the electric power steering control computing means;
A function of calculating a first steering angle based on the steering angle signal, calculating a second steering angle based on the motor rotation angle signal, and calculating a third steering angle based on the yaw rate signal; The electric power steering control abnormality monitoring means detects that the electric power steering control calculating means is not abnormal, and deviations between the first steering angle, the second steering angle, and the third steering angle are respectively detected. Steering angle calculation means for determining that the first steering angle is abnormal when larger than a predetermined value is provided.

Further, the vehicle steering apparatus according to the present invention includes steering torque detection means for detecting a steering torque based on a signal generated in response to a steering torque applied to a steering shaft of the vehicle by a driver and outputting a steering torque signal. ,
Motor rotation angle detecting means for detecting a motor rotation angle based on a signal generated corresponding to a rotation angle of an assist motor for applying assist torque to the steering shaft and outputting a motor rotation angle signal;
Vehicle speed detection means for detecting a vehicle speed based on a signal generated corresponding to the vehicle speed of the vehicle and outputting a vehicle speed signal;
Electric power steering control calculating means for calculating an assist command value based on at least the motor rotation angle signal, the steering torque signal, and the vehicle speed signal;
Motor driving means for driving the assist motor based on the assist command value;
Steering angle detection means for detecting a steering angle based on a signal generated corresponding to the rotation angle of the steering shaft and outputting a steering angle signal;
Wheel speed detecting means for detecting a four-wheel wheel speed based on a signal corresponding to a wheel speed of each of the four wheels of the vehicle and outputting a four-wheel wheel speed signal;
Electric power steering control abnormality monitoring means for detecting the presence or absence of abnormality of the electric power steering control computing means;
A function of calculating a first steering angle based on the steering angle signal, calculating a second steering angle based on the motor rotation angle signal, and calculating a third steering angle based on the four-wheel wheel speed signal. The electric power steering control abnormality monitoring means detects that the electric power steering control arithmetic means is not abnormal, and the first steering angle, the second steering angle, and the third steering angle Steering angle calculation means for determining that the first steering angle is abnormal when the deviation is larger than a predetermined value.

  In the vehicle steering apparatus according to the present invention, preferably, the electric power steering control abnormality monitoring means detects that the electric power steering control calculating means is not abnormal, and the first steering angle and the second steering are detected. When the deviation between the angle and the third steering angle is less than or equal to the predetermined value, or the abnormality of the electric power steering control calculating means is detected by the electric power steering control abnormality monitoring means, and the first When the deviation between the steering angle and the third steering angle is equal to or less than the predetermined value, the first steering angle is set as the steering angle of the vehicle.

  Furthermore, in the vehicle steering apparatus according to the present invention, preferably, the electric power steering control abnormality monitoring means detects that the electric power steering control calculating means is not abnormal, and the first steering angle and the second steering are detected. When the deviation between the angle and the third steering angle is larger than the predetermined value, the third steering angle is set as the steering angle of the vehicle.

  In addition, the vehicle steering apparatus according to the present invention preferably includes a steering angle calculation abnormality monitoring unit that detects the presence or absence of abnormality of the steering angle calculation unit, and the electric power steering control calculation unit includes the motor rotation angle signal. When the steering angle calculation abnormality monitoring device detects an abnormality in the steering angle calculation means, and the calculation for the electric power steering control is performed. The absolute steering angle calculated by the means is used as the steering angle of the vehicle.

  Furthermore, in the vehicle steering apparatus according to the present invention, preferably, the electric power steering control calculating means and the steering angle calculating means are housed in the same casing.

  According to the vehicle steering apparatus of the present invention, the steering angle detecting means for detecting the steering angle based on the signal generated corresponding to the rotation angle of the steering shaft and outputting the steering angle signal, and the electric power steering control calculating means And a function for calculating a first steering angle based on the steering angle signal and calculating a second steering angle based on the motor rotation angle signal. When the electric power steering control abnormality monitoring means detects that the electric power steering control calculating means is normal and the deviation between the first steering angle and the second steering angle is greater than a predetermined value, the first steering angle is A steering angle calculation means for determining that the steering angle is abnormal. The presence or absence of abnormality of the grayed angle signal can be determined accurately.

  According to the vehicle steering apparatus of the present invention, the electric power steering control abnormality monitoring means detects that the electric power steering control calculating means is not abnormal, and the deviation between the first steering angle and the second steering angle. Is less than a predetermined value, or when the abnormality of the electric power steering control computing means is detected by the electric power steering control abnormality monitoring means, the first steering angle is set as the steering angle of the vehicle. , You can always get an accurate steering angle.

  Further, in the vehicle steering system according to the present invention, the electric power steering control abnormality monitoring means detects that the electric power steering control calculating means is not abnormal, and the deviation between the first steering angle and the second steering angle is When it is larger than the predetermined value, the second steering angle is set as the steering angle of the vehicle, so that an accurate steering angle can always be obtained.

  According to the vehicle steering apparatus of the present invention, the steering angle detecting means for detecting the steering angle based on the signal generated corresponding to the rotation angle of the steering shaft and outputting the steering angle signal, the yaw rate of the vehicle The yaw rate detecting means for detecting the yaw rate based on the signal corresponding to the output and outputting the yaw rate signal, the electric power steering control abnormality monitoring means for detecting the presence / absence of abnormality of the electric power steering control calculating means, and the first based on the steering angle signal A function of calculating one steering angle, calculating a second steering angle based on the motor rotation angle signal, and calculating a third steering angle based on the yaw rate signal; No abnormality is detected in the control calculation means, and the first steering angle and the second steering angle are detected. Steering angle calculation means for determining that the first steering angle is abnormal when the deviation between the ring angle and the third steering angle is greater than a predetermined value. The presence or absence of an abnormality in the steering angle signal can be determined more accurately.

  Further, according to the vehicle steering apparatus of the present invention, the steering angle detecting means for detecting the steering angle based on the signal generated corresponding to the rotation angle of the steering shaft and outputting the steering angle signal, the four wheels of the vehicle An abnormality for electric power steering control that detects the presence or absence of abnormality in the wheel speed detection means for detecting the four wheel speed based on the signal corresponding to each wheel speed and outputting the four wheel speed signal and the electric power steering control computing means. Monitoring means; calculating a first steering angle based on the steering angle signal; calculating a second steering angle based on the motor rotation angle signal; and calculating a third steering angle based on the four-wheel wheel speed signal. The abnormality monitoring means for electric power steering control having a function for calculating detects that there is no abnormality in the electric power steering control calculating means, and the first steering angle and the second Steering angle calculation means for determining that the first steering angle is abnormal when the deviation between the tearing angle and the third steering angle is greater than a predetermined value. The presence or absence of an abnormality in the steering angle signal can be determined more accurately.

  Further, according to the vehicle steering apparatus of the present invention, the electric power steering control abnormality monitoring means detects that the electric power steering control arithmetic means is not abnormal, and the first steering angle, the second steering angle, and the third steering angle. Between the first steering angle and the third steering angle when the deviation between the first steering angle and the third steering angle is not more than a predetermined value, or the abnormality of the electric power steering control arithmetic means is detected by the electric power steering control abnormality monitoring means. When the deviation is less than or equal to a predetermined value, the first steering angle is set as the steering angle of the vehicle, so that an accurate steering angle can always be obtained.

  Further, according to the vehicle steering apparatus of the present invention, the electric power steering control abnormality monitoring means detects that there is no abnormality in the electric power steering control calculating means, and the first steering angle, the second steering angle, and the third steering are detected. When the deviation from each other is greater than a predetermined value, the third steering angle is set as the vehicle steering angle, so that an accurate steering angle can always be obtained.

  According to the vehicle steering apparatus of the present invention, the steering angle calculation abnormality monitoring means for detecting whether or not the steering angle calculation means is abnormal is provided, and the electric power steering control calculation means outputs the motor rotation angle signal to the absolute value of the steering shaft. It has a function to calculate the steering absolute angle converted into the angle signal. When an abnormality of the steering angle calculation means is detected by the steering angle calculation abnormality monitoring device, the steering absolute angle generated by the electric power steering control calculation means is calculated. Since the vehicle steering angle is used, an accurate steering angle can be obtained by the electric power steering control calculating means even when the steering angle calculating means is abnormal.

  Further, according to the vehicle steering apparatus of the present invention, since the electric power steering control calculating means and the steering angle calculating means are housed in the same casing, communication delays, harnesses connecting the respective casings, etc. Abnormalities can be prevented.

Embodiment 1 FIG.
Hereinafter, a vehicle steering apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing the overall configuration of a vehicle steering system including a vehicle steering apparatus according to Embodiment 1 of the present invention. In FIG. 1, a vehicle steering system includes a steering shaft 2 having a steering handle 1 provided at the upper end, a steering gear box 3 provided at the lower end of the steering shaft 2, a rack and a pinion coupled to the gear box 3. A mechanism 6 and a tire 7 that is steered by a rack and pinion mechanism 6 are included.

  Further, the vehicle steering system includes a steering angle sensor 9 provided on the steering shaft 2, a torque sensor 4 provided on the steering shaft 2, an assist motor 5 connected to the steering shaft 2 via a speed reduction mechanism, an assist A vehicle steering device 8 including a motor driver for controlling the motor 5 and a cable (not shown) for connecting the steering angle sensor 9, the torque sensor 4, the assist motor 5 and the vehicle steering device 8 described above are included. . In addition, although not shown in figure, naturally a power supply device is also included.

  The steering angle sensor 9 detects the absolute rotation angle of the steering handle 1, that is, the absolute rotation angle of the steering shaft 2, and outputs a steering angle detection signal θs. The torque sensor 4 detects the steering torque applied to the steering shaft 2 by the driver via the steering handle 1 and outputs a steering torque detection signal Thdl.

  The assist motor 5 is configured by an electric motor, and applies an assist torque Tassist corresponding to the steering torque by the driver to the steering shaft 2 to assist steering by the driver. A resolver (not shown) as a motor rotation angle sensor provided in the assist motor 5 outputs a motor rotation angle detection signal θm corresponding to the rotation angle of the rotor of the assist motor 5.

  The steering gear box 3 provided at the lower end of the steering shaft 2 amplifies the combined torque obtained by adding the steering torque applied to the steering shaft 2 and the assist torque from the assist motor 5 several times, and thereby the rack and pinion mechanism 6 is To the steering mechanism for steering the tire 7 via

  As will be described later, the vehicle steering apparatus 8 according to Embodiment 1 of the present invention drives the assist motor 5 with the motor drive current Imtr, and also determines the steering angle abnormality signal θfail when determining that the steering angle signal is abnormal. Output.

  FIG. 2 is a block diagram showing the configuration of the vehicle-mounted steering device 8 according to Embodiment 1 of the present invention. In FIG. 2, a vehicle-mounted steering device 8 includes a vehicle speed detector 11 as vehicle speed detection means, a steering torque detector 12 as steering torque detection means, and motor rotation detectors 13 as motor rotation angle detection means. A steering angle detector 14 as a steering angle detection means, an electric power steering control calculator 15 as an electric power steering control calculating means, and an electric power steering control abnormality monitor 16 as an electric power steering control abnormality monitoring means. A steering angle calculator 17 as a steering angle calculator and a motor driver 19 as a motor driver are provided.

  The vehicle speed detector 11 detects the vehicle speed based on the vehicle speed detection signal V corresponding to the vehicle speed and outputs a vehicle speed signal V (s). The steering torque detector 12 detects a steering torque based on the steering torque detection signal Thdl from the torque sensor 4 and outputs a steering torque signal Thdl (s). The motor rotation angle detector 13 detects a motor rotation angle based on a motor rotation angle detection signal θm from a resolver provided in the assist motor 5 and outputs a motor rotation angle signal θm (s). The steering angle detector 14 detects a steering angle based on the steering angle detection signal θs from the steering angle sensor 9 and outputs a steering angle signal θs (s).

  The electric power steering control calculator 15 includes a vehicle speed signal V (s) input from the vehicle speed detector 11, a steering torque signal Thdl (s) input from the steering torque detector 12, and a motor rotation angle detector 13. Based on the input motor rotation angle signal θm (s), an assist torque to be applied to the steering shaft 2 is calculated, and a command value for applying the calculated assist torque to the steering shaft 2 via the speed reduction mechanism is generated. And output to the motor driver 19.

  The electric power steering control computing unit 15 generates a command value for exciting the above-described resolver winding provided in the assist motor 5 and supplies the command value to the resolver. The resolver is excited based on a command value from the electric power steering control calculator 15, generates a motor rotation angle detection signal θm corresponding to the rotation angle of the rotor of the assist motor 5, and inputs it to the motor rotation angle detector 13. To do. The electric power steering control calculator 15 has various other functions not related to the present invention, but the description thereof is omitted here.

The motor driver 19 receives the assist torque command value from the electric power steering control calculator 15 and the motor drive current detection signal Imtr from the assist motor 5, and uses the input command value as a control target value to assist motor. 5 is generated and applied to the assist motor 5. The assist motor 5 is driven based on the drive current input from the motor driver 19.

  In addition to the above, a signal corresponding to the state of the vehicle, such as the yaw rate, is input to the in-vehicle steering device 8, but this is not related to the vehicle steering device according to the first embodiment of the present invention, so that explanation will be given. Is omitted.

  The electric power steering control abnormality monitor 16 transmits / receives a predetermined signal to / from the electric power steering control calculator 15, and a status signal indicating the operating state of the electric power steering control calculator 15 obtained based on the transmission / reception. To determine whether there is an abnormality in the electric power steering control computing unit 15 and output the determination result. That is, for example, a predetermined pulse signal is transmitted and received between the electric power steering control abnormality monitoring device 16 and the electric power steering control computing unit 15 at regular time intervals, and the electric power steering control is based on the reception timing of the pulse signal. The abnormality determination of the arithmetic unit 15 is performed, and the determination result is output.

  Based on the pulse signal from the electric power steering control calculator 15, for example, the electric power steering control abnormality monitor 16 determines whether the state of the electric power steering control calculator 15 is abnormal due to a failure in the excitation portion of the resolver or the like. Alternatively, it is possible to identify the abnormal contents of the electric power steering control computing unit 15 such as whether or not the electric power steering control computing unit 15 is down due to a failure of the power source or the like.

  The electric power steering control abnormality monitoring device 16 has a function of performing the same calculation as that of the electric power steering control calculator 15 and compares the calculation result with the calculation result of the electric power steering control calculator 15. An abnormality determination of the power steering control calculator 15 may be performed. Furthermore, the electric power steering control arithmetic unit 15 has the function of the electric power steering control abnormality monitor 16 as a self-abnormality determination unit. That is, the electric power steering control arithmetic unit 15 includes the electric power steering control abnormality monitor 16. You may make it let.

As will be described later, the steering angle calculator 17 calculates the first steering angle θhs (s) based on the steering angle signal θs (s) from the steering angle detector 14, and outputs from the motor rotation angle detector 13. Based on the motor rotation angle signal θm (s), the second steering angle θms (s) is calculated. Then, it is determined whether or not the first steering angle θhs (s) is abnormal. When the first steering angle θhs (s) is abnormal, a steering angle abnormality signal θfail is output.

  In the vehicle steering system including the vehicle steering device 8 according to the first embodiment of the present invention configured as described above, when steering torque is applied to the steering handle 1 by the driver, the electric power steering control computing unit 15. Calculates the assist torque as described above, and outputs a command value to the motor driver 19. As a result, the motor driver 19 generates a drive current corresponding to the command value given from the electric power steering control computing unit 15 and gives it to the assist motor 5 to drive the assist motor 5. As a result, an assist torque corresponding to the steering torque by the driver is applied from the assist motor 5 to the steering shaft 2 via the speed reduction mechanism, and the vehicle is based on the sum of the steering torque by the driver and the assist torque by the assist motor 5. Is steered.

  Next, the operation of the vehicle steering apparatus 8 according to Embodiment 1 of the present invention will be described. FIG. 3 is a flowchart showing main operations of the vehicle steering apparatus 8 according to the first embodiment of the present invention. In FIG. 3, first, in step S101, the steering angle calculator 17 reads the motor rotation angle signal θm (s) from the motor rotation angle detector 13 and stores it in its own memory (not shown). To do.

  Subsequently, in step S102, the steering angle calculator 17 calculates the steering relative angle θhm (s) by dividing the stored motor rotation angle signal θm (s) by the reduction gear ratio of the assist motor 5, and further, By subtracting the difference between the steering angle initial value θs (0) and the steering relative angle initial value θhm (0) from the calculated steering relative angle θhm (s), the steering relative angle θhm (s) is converted into an absolute steering angle. The converted steering absolute angle value is stored in its own memory as the second steering angle θms (s).

Next, in step S103, the steering angle calculator 17 reads the steering angle signal θs (s) from the steering angle detector 14, and this steering angle signal θs (
Based on s), the first steering angle θhs (s) is calculated and stored in its own memory. In step 104, the electric power steering control abnormality monitor 16 stores the state signal of the electric power steering control computing unit 15 in its own memory, and in step S105, based on the stored state signal. Then, it is determined whether or not the electric power steering control computing unit 15 is abnormal.

  As a result of the determination in step S105, if it is determined that the electric power steering control calculator 15 is abnormal, the second steering angle θms (s) calculated by the steering angle calculator 17 is accurately determined as the steering angle. Cannot be assumed to be a value indicating. That is, as described above, the winding of the resolver provided in the assist motor 5 is excited based on the command value from the electric power steering control computing unit 15, and the electric power steering control computing unit 15 is abnormal. If there is, there is a possibility that the motor rotation angle detection signal θm itself from the resolver is abnormal, and accordingly, the second steering angle θm (s) generated based on this motor rotation angle detection signal θm. Reliability cannot be ensured.

Accordingly, when an abnormality of the electric power steering control computing unit 15 is detected as a result of the determination in step S105, the steering angle computing unit 17 does not proceed to step S106 but the steering angle computing unit 17 is not shown. The steering angle θhs (s) is used as a vehicle steering angle for necessary calculations.

As a result of the determination in step S105, when it is determined that the electric power steering control computing unit 15 is not abnormal, the process proceeds to step S106. In step S106, the steering angle calculator 17 calculates a difference between the first steering angle θhs (s) and the second steering angle θms (s) stored in its own memory. Then, the difference is compared with a preset value α. At this time, when the unit of each angle signal is calculated by “degree (°)”, the preset value α is set to a value of about “3 degrees (°)”, for example. The preset value α varies depending on the resolution of the steering angle sensor 9 and the like.

  Next, the process proceeds to step S107, and the steering angle calculator 17 sets a difference between the first steering angle θhs (s) and the second steering angle θms (s) in advance as a result of the comparison in step S106. It is determined whether or not it is greater than the value α. As a result of the determination in step S107, if it is determined that the above difference is greater than a preset value α, the process proceeds to step S108.

  In step S108, the steering angle calculator 17 determines that the difference between the first steering angle θhs (s) and the second steering angle θms (s) is greater than a preset value α, It is determined that the steering angle θhs (s) is abnormal, a steering angle abnormality signal θfail is output, and the second steering angle θms (s) is used as a vehicle steering angle for necessary calculations.

  As a result of the determination in step S107, if it is determined that the difference between the first steering angle θhs (s) and the second steering angle θms (s) is equal to or smaller than a preset value α, FIG. Although not shown, the steering angle calculator 17 uses the first steering angle θhs (s) as a vehicle steering angle for necessary calculations.

  As described above, according to the vehicle-mounted steering apparatus according to Embodiment 1 of the present invention, the presence / absence of abnormality of the electric power steering control computing unit 15 is confirmed, and the validity of the second steering angle θms (s) is confirmed. After that, the first steering angle θhs (s) and the second steering angle θms (s) are compared, so the presence or absence of an abnormality in the first steering angle θhs (s) is detected with high accuracy. be able to. That is, by checking the presence / absence of abnormality of the electric power steering control computing unit 15 by the electric power steering control abnormality monitor 17, it becomes possible to consider at least the reliability of the motor rotation angle. The presence or absence of an abnormality in θhs (s) can be detected with high accuracy.

In the first embodiment of the present invention described above, in order to convert the steering relative angle θhm (s) obtained from the motor rotation angle signal θm (s) into an absolute angle, the steering angle initial value θs (0) Although the difference of the steering relative angle initial value θhm (0) is calculated, for example, the four wheel speeds of the vehicle are taken and the steering relative angle when these four wheel speeds are the same is set to “0” degrees. The absolute angle may be obtained from the relative angle by various known means such as providing means. In this case, the second steering angle θms (s) can be calculated from only the current information without maintaining the steering relative angle initial value θhm (0).

  Further, the first steering angular velocity is calculated from the steering angular signal θs (s), the second steering angular velocity is calculated from the motor rotational angle signal θm (s), and the first steering angular velocity and the second steering angular velocity are calculated. When the difference is larger than a preset value α, an abnormality of the first steering angle signal θs (s) may be detected.

  The electric power steering control calculator 15 and the steering angle calculator 17 are elements capable of performing signal processing operations such as a CPU, a DSP (data processing system), an FPGA (field programmable gate array), an ASIC (specific application integrated circuit), and the like. Any of them may be used, and in that case, the electric power steering control computing unit 15 and the steering angle computing unit 17 can be housed in one casing. By storing the electric power steering control computing unit 15 and the steering angle computing unit 17 in a single housing, communication delays and abnormalities such as harnesses connecting the respective housings can be prevented rather than providing separate housings. It becomes possible to do.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing a configuration of a vehicle steering apparatus according to Embodiment 2 of the present invention. The vehicle steering apparatus according to the second embodiment shown in FIG. 4 outputs the yaw rate signal γ (s) of the vehicle based on the signal γ corresponding to the yaw rate of the vehicle to the vehicle steering apparatus according to the first embodiment. A detector 40 is added to output a correct steering angle θ in addition to the first steering angle abnormality detection signal θfail output from the steering angle calculator 17. In the following description, differences from the first embodiment will be mainly described.

  FIG. 5 is a flowchart showing the operation of the vehicle steering apparatus according to Embodiment 2 of the present invention. In FIG. 5, Steps S201 to S203 correspond to Steps S101 to S103 of FIG. 3 in Embodiment 1 described above and are the same as those described above, so description thereof will be omitted.

但し、Ｌは車両のホイールベース、Ｖは車速、Ａは車両のスタビリティファクタ、Ｇｒｐはラックアンドピニオン部のステアリングギア比である。一般的にこれらの何れのパラメータも車両に応じて一意に設定される数値であり、予めメモリに記憶しておくことで演算が可能となる。尚、式（１）による演算以外の演算により、ヨーレート信号γ（ｓ）から第３のステアリング角を得るようにしてもよい。 In step S204, the steering angle calculator 17 reads the yaw rate signal γ (s) from the yaw rate detector 40 corresponding to the yaw rate γ of the vehicle, and based on the yaw rate signal γ (s), the third steering angle θys ( s) is calculated by, for example, the following equation (1), and the calculation result is stored in its own memory.

Where L is the vehicle wheelbase, V is the vehicle speed, A is the vehicle stability factor, and Grp is the steering gear ratio of the rack and pinion section. In general, any of these parameters is a numerical value that is uniquely set according to the vehicle, and can be calculated by storing it in a memory in advance. Note that the third steering angle may be obtained from the yaw rate signal γ (s) by a calculation other than the calculation according to the equation (1).

  Next, in step S205, the electric power steering control abnormality monitor 16 reads the status signal of the electric power steering control computing unit 15 and stores it in its own memory, and proceeds to step S206, where the stored status signal is added. Based on this, it is determined whether the electric power steering control computing unit 15 is normal or abnormal.

  As a result of the determination in step S206, if it is determined that the electric power steering control computing unit 15 is abnormal, the process proceeds to step S207. In step S207, the steering angle calculator 17 compares the difference between the first steering angle θhs (s) and the third steering angle θys (s) with a preset value α.

  If the result of determination in step S207 is that the difference between the first steering angle θhs (s) and the third steering angle θys (s) is less than or equal to a preset value α, processing proceeds to step S208. The first steering angle θhs (s) is determined to be normal, and the steering angle calculator 17 outputs the first steering angle θhs (s) as the steering angle θ of the vehicle.

  On the other hand, if the result of determination in step S207 is that the difference between the first steering angle θhs (s) and the third steering angle θys (s) is greater than a preset value α, processing proceeds to step S210. The steering angle calculator 17 does not output the steering angle θ. Then, the process proceeds from step S210 to step S211, where it is determined that the first steering angle θhs (s) is abnormal, and the steering angle abnormality detection signal θfail is output.

  As a result of the determination in step S206 described above, if it is determined that the electric power steering control calculator 15 is not abnormal, the process proceeds to step S209, where the first steering angle θhs (s) and the second steering angle θms. The difference between (s) and the third steering angle θys (s), that is, the difference between the first steering angle θhs (s) and the second steering angle θms (s), and the first The difference between the steering angle θhs (s) and the third steering angle θys (s) and the difference between the second steering angle θms (s) and the third steering angle θys (s) Calculate each one.

  Next, proceeding to step S212, the steering angle calculator 17 compares all the differences calculated in step S209 with a preset value α, and if each difference is equal to or less than the preset value α. In step S213, the first steering angle θhs (s) is output as the steering angle θ of the vehicle.

  On the other hand, if it is determined in step S212 that all the differences calculated in step S209 are compared with the preset value α, each difference is greater than the preset value α, the process proceeds to step S214. The steering angle calculator 17 outputs the second steering angle θms (s) as the steering angle θ. In step S215, the steering angle calculator 17 determines that the first steering angle θhs (s) is abnormal, and outputs a steering angle abnormality signal θfail.

  According to the vehicle steering apparatus according to the second embodiment of the present invention described above, the CPU of the electric power steering control calculator 15 becomes abnormal by calculating the third steering angle θys (s) from the yaw rate. Even in this case, it is possible to detect the steering angle signal from the steering angle detector 14 and thus the abnormality of the steering angle sensor 9. Further, by outputting the steering angle θ from the steering angle calculator 17, even if the first steering angle θhs (s) becomes abnormal, the second steering angle θms (s) is output as the steering angle θ. It is possible to operate a system such as a skid prevention device that requires a steering angle θ.

  The steering angle calculator 17 not only outputs the steering angle θ in response to the determination result of whether or not the state of the electric power steering control arithmetic unit 15 by the electric power steering control abnormality monitor 16 is abnormal, The state of the power steering control calculator 15 may also be output. For example, when the state of the electric power steering control computing unit 15 is determined to be abnormal due to failure of the excitation portion of the resolver, a signal indicating that the electric power steering control computing unit 15 is abnormal is output, and the power source or the like For example, when the electric power steering control calculator 15 is down due to a failure, a signal indicating that the electric power steering control calculator 15 is in the down state may be output.

  When the signal indicating that the electric power steering control calculator 15 is in the down state is output, for example, a device that requires the steering angle as a control element, such as a skid prevention device, the electric power steering control calculator 15 is in the down state. In consideration of the fact, it is possible to take measures such as limiting the operation range of the control using the steering angle.

  The electric power steering control calculator 15 and the steering angle calculator 17 are elements capable of performing signal processing operations such as a CPU, a DSP (data processing system), an FPGA (field programmable gate array), an ASIC (specific application integrated circuit), and the like. Any of them may be used, and in that case, the electric power steering control computing unit 15 and the steering angle computing unit 17 can be housed in one casing. By storing the electric power steering control computing unit 15 and the steering angle computing unit 17 in a single housing, communication delays and abnormalities such as harnesses connecting the respective housings can be prevented rather than providing separate housings. It becomes possible to do.

  As described above, according to the vehicle steering apparatus of the second embodiment of the present invention, after confirming that the electric power steering control calculator 15 is normal, the first steering angle θhs (s) is abnormal. Therefore, the presence / absence of the first steering angle abnormality can be accurately detected. That is, by checking the presence / absence of abnormality of the electric power steering control computing unit 15 by the electric power steering control abnormality monitor 17, it becomes possible to consider at least the reliability of the motor rotation angle. The presence or absence of an abnormality in θhs (s) can be detected with high accuracy.

  Further, since the third steering angle is calculated based on the yaw rate signal, it is possible to detect an abnormality in the first steering angle even when an abnormality occurs in the electric power steering control calculator 15. Become.

  In the above-described vehicle steering apparatus according to the second embodiment of the present invention, the yaw rate detector 40 is provided and the third steering angle is calculated based on the yaw rate signal, but instead of the yaw rate detector. A wheel speed detector may be provided as wheel speed detecting means for detecting the four-wheel wheel speed based on a signal corresponding to the wheel speed of each of the four wheels of the vehicle and outputting the four-wheel wheel speed signal. In this case, the steering relative angle when the four-wheel wheel speeds are the same can be regarded as “0” degrees, and the third steering angle is calculated by the steering angle calculator 17 using this. Others are the same as those of the second embodiment shown in FIGS.

  In addition to the above-described configuration, the third steering angle can be calculated using other vehicle state quantities corresponding to the steering angle.

Embodiment 3 FIG.
FIG. 6 is a block diagram showing the configuration of the vehicle steering apparatus according to Embodiment 3 of the present invention. The vehicle steering apparatus according to the third embodiment adds a steering angle calculation abnormality monitor 60 to the vehicle steering apparatus according to the second embodiment shown in FIG. 4 and monitors the state of the steering angle calculator 17 to An anomaly is detected. Other configurations are the same as those of the vehicle steering apparatus according to the second embodiment.

  In FIG. 6, a steering angle calculation abnormality monitor 60 as a steering angle calculation abnormality monitoring means has a function of exchanging the internal state of the steering angle calculation unit 17 by communication and monitoring the abnormality of the steering angle calculation unit 17. . For example, a predetermined pulse signal is transmitted and received between the steering angle calculation abnormality monitor 60 and the steering angle calculator 17 at regular time intervals, and the steering angle is calculated based on the reception timing of the pulse signal from the steering angle calculator 17. An abnormality determination of the arithmetic unit 17 is performed.

  Based on the pulse signal from the steering angle calculator 17, the steering angle calculation abnormality monitor 40 determines whether the steering angle calculator 17 is abnormal due to heat generation or the like. It is also possible to identify the abnormal contents of the electric power steering control computing unit 15 such as whether or not 17 is down due to a failure of the power source or the like.

  Alternatively, the steering angle calculation abnormality monitor 60 performs a calculation equivalent to the steering angle calculator 17 and compares the calculation result with the calculation result of the steering angle calculator 17 to determine the abnormality of the steering angle calculator 17. You may do it. Further, even if the steering angle calculator 17 has the function of the steering angle calculation abnormality monitor 60 as a self-abnormality determination unit, the same effect can be obtained.

  The electric power steering control computing unit 15 communicates with the steering angle computing unit 17 to obtain the steering angle θs (s) and the state of the steering angle computing unit 17. The electric power steering control calculator 15 calculates the difference between the steering angle initial value θs (0) and the steering relative angle initial value θhm (0) in order to convert the steering relative angle obtained from the motor rotation angle into an absolute angle. And has a function of calculating the steering angle θ.

  When the steering angle calculation abnormality monitor 17 detects an abnormality in the steering angle calculator 17, the electric power steering control calculator 15 outputs the steering angle θ calculated as described above.

  Further, the electric power steering control computing unit 15 can obtain the state of the steering angle computing unit by communicating with the steering angle computing unit 17, so that it not only outputs the steering angle θ but also the state of the steering angle computing unit 17. May also be output. For example, when it is determined that the steering angle calculator 17 is abnormal due to heat generation or the like, the steering angle calculator 17 outputs a signal indicating that the steering angle calculator 17 is abnormal, and the steering angle calculator 17 is faulty due to a failure of the power source or the like. When 17 is down, a signal indicating that the steering angle calculator 17 is in the down state can be output.

  The electric power steering control calculator 15 and the steering angle calculator 17 are elements capable of performing signal processing operations such as a CPU, a DSP (data processing system), an FPGA (field programmable gate array), an ASIC (specific application integrated circuit), and the like. Any of them may be used, and in that case, the electric power steering control computing unit 15 and the steering angle computing unit 17 can be housed in one casing. By storing the electric power steering control computing unit 15 and the steering angle computing unit 17 in a single housing, communication delays and abnormalities such as harnesses connecting the respective housings can be prevented rather than providing separate housings. It becomes possible to do.

  As described above, according to the vehicle steering apparatus of the second embodiment of the present invention, after confirming that the electric power steering control calculator 15 is normal, the first steering angle θhs (s) is abnormal. Therefore, the presence / absence of the first steering angle abnormality can be accurately detected. That is, by checking the presence / absence of abnormality of the electric power steering control computing unit 15 by the electric power steering control abnormality monitor 17, it becomes possible to consider at least the reliability of the motor rotation angle. The presence or absence of an abnormality in θhs (s) can be detected with high accuracy.

  As described above, the vehicle steering apparatus according to Embodiment 3 of the present invention includes the steering angle calculation abnormality monitor 60 that monitors the steering angle calculator 17 for abnormality, and the electric power steering control calculator 15 includes the motor. Since the steering relative angle obtained from the rotation angle is converted into an absolute angle, the difference between the steering angle initial value θs (0) and the steering relative angle initial value θhm (0) is calculated, and the steering angle θ is calculated. Even when an abnormality occurs in the steering angle calculator 17, the steering angle θ can be obtained with high accuracy.

Embodiment 4 FIG.
Although the vehicle steering apparatus according to Embodiment 4 of the present invention is not shown, the electric power steering control computing unit 15 and the steering angle computing unit 17 are each provided with an independent power source in the vehicle steering system 8. It is characterized by doing so. Other configurations are the same as the configurations of the first to third embodiments described above.

  In this way, the electric power steering control computing unit 15 and the steering angle computing unit 17 are each provided with an independent power source, so that even if an abnormality occurs in one power source, the other computing unit is normal. Therefore, it is possible to continuously calculate the steering angle θ.

Embodiment 5 FIG.
Although not shown, the vehicle steering apparatus according to the fifth embodiment of the present invention is provided with the ground for the electric power steering control calculator 15 and the steering angle calculator 17 in the vehicle steering apparatus 8 separately. To do. Other configurations are the same as the configurations of the first to fourth embodiments described above.

  As described above, by providing the power steering control computing unit 15 and the steering angle computing unit 17 independently with the ground, it is possible to prevent communication abnormality due to noise or the like, and to calculate the steering angle θ with high accuracy. Is possible.

  The vehicle steering apparatus according to the present invention is not limited to the first to fifth embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

It is explanatory drawing which shows the whole structure of the steering system of the vehicle containing the steering apparatus for vehicles by Embodiment 1 of this invention. It is a block diagram which shows the structure of the vehicle-mounted steering apparatus by Embodiment 1 of this invention. 3 is a flowchart showing main operations of the vehicle steering apparatus according to Embodiment 1 of the present invention. It is a block diagram which shows the structure of the vehicle steering device by Embodiment 2 of this invention. It is a flowchart which shows the main operation | movement of the steering apparatus for vehicles by Embodiment 2 of this invention. It is a block diagram which shows the structure of the steering apparatus for vehicles by Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering 2 Steering shaft 3 Steering gear box 4 Torque sensor 5 Assist motor 6 Rack and pinion mechanism 7 Tire 8 Vehicle steering device 9 Steering angle sensor 11 Vehicle speed detector 12 Steering torque detector 13 Motor rotation angle detector 14 Steering angle detection 15 Electric power steering control arithmetic unit 16 Electric power steering control abnormality monitor 17 Steering angle calculator 19 Motor driver 40 Yaw rate detector 60 Steering angle calculation abnormality monitor

Claims (13)

Steering torque detection means for detecting a steering torque based on a signal generated in response to a steering torque applied to a steering shaft of a vehicle by a driver and outputting a steering torque signal;
Motor rotation angle detecting means for detecting a motor rotation angle based on a signal generated corresponding to a rotation angle of an assist motor for applying assist torque to the steering shaft and outputting a motor rotation angle signal;
Vehicle speed detection means for detecting a vehicle speed based on a signal generated corresponding to the vehicle speed of the vehicle and outputting a vehicle speed signal;
Electric power steering control calculating means for calculating an assist command value based on at least the motor rotation angle signal, the steering torque signal, and the vehicle speed signal;
Motor driving means for driving the assist motor based on the assist command value;
Steering angle detection means for detecting a steering angle based on a signal generated corresponding to the rotation angle of the steering shaft and outputting a steering angle signal;
Electric power steering control abnormality monitoring means for detecting the presence or absence of abnormality of the electric power steering control computing means;
A function of calculating a first steering angle based on the steering angle signal and a second steering angle based on the motor rotation angle signal; and the electric power steering control abnormality monitoring means for the electric power steering control. Steering angle for determining that the first steering angle is abnormal when no abnormality is detected in the computing means and the deviation between the first steering angle and the second steering angle is greater than a predetermined value A vehicle steering apparatus comprising: an arithmetic means.   When the electric power steering control abnormality monitoring means detects that the electric power steering control calculating means is not abnormal and the deviation between the first steering angle and the second steering angle is not more than the predetermined value, Alternatively, when the abnormality of the electric power steering control calculating means is detected by the electric power steering control abnormality monitoring means, the first steering angle is set as the steering angle of the vehicle. The steering apparatus for vehicles as described.   When the electric power steering control abnormality monitoring means detects no abnormality of the electric power steering control calculating means and the deviation between the first steering angle and the second steering angle is larger than the predetermined value, The vehicle steering apparatus according to claim 1, wherein the second steering angle is a steering angle of the vehicle. Steering torque detection means for detecting the steering torque based on a signal generated in response to the steering torque applied to the steering shaft of the vehicle by the driver and outputting a steering torque signal;
Motor rotation angle detecting means for detecting a motor rotation angle based on a signal generated corresponding to a rotation angle of an assist motor for applying assist torque to the steering shaft and outputting a motor rotation angle signal;
Vehicle speed detection means for detecting a vehicle speed based on a signal generated corresponding to the vehicle speed of the vehicle and outputting a vehicle speed signal;
Electric power steering control calculating means for calculating an assist command value based on at least the motor rotation angle signal, the steering torque signal, and the vehicle speed signal;
Motor driving means for driving the assist motor based on the assist command value;
Steering angle detection means for detecting a steering angle based on a signal generated corresponding to the rotation angle of the steering shaft and outputting a steering angle signal;
Yaw rate detection means for detecting a yaw rate based on a signal corresponding to the yaw rate of the vehicle and outputting a yaw rate signal;
Electric power steering control abnormality monitoring means for detecting the presence or absence of abnormality of the electric power steering control computing means;
A function of calculating a first steering angle based on the steering angle signal, calculating a second steering angle based on the motor rotation angle signal, and calculating a third steering angle based on the yaw rate signal; The electric power steering control abnormality monitoring means detects no abnormality of the electric power steering control calculating means, and deviations between the first steering angle, the second steering angle, and the third steering angle are respectively detected. A steering apparatus for a vehicle, comprising: a steering angle calculation unit that determines that the first steering angle is abnormal when larger than a predetermined value. Steering torque detection means for detecting the steering torque based on a signal generated in response to the steering torque applied to the steering shaft of the vehicle by the driver and outputting a steering torque signal;
Motor rotation angle detecting means for detecting a motor rotation angle based on a signal generated corresponding to a rotation angle of an assist motor for applying assist torque to the steering shaft and outputting a motor rotation angle signal;
Vehicle speed detection means for detecting a vehicle speed based on a signal generated corresponding to the vehicle speed of the vehicle and outputting a vehicle speed signal;
Electric power steering control calculating means for calculating an assist command value based on at least the motor rotation angle signal, the steering torque signal, and the vehicle speed signal;
Motor driving means for driving the assist motor based on the assist command value;
Steering angle detection means for detecting a steering angle based on a signal generated corresponding to the rotation angle of the steering shaft and outputting a steering angle signal;
Wheel speed detecting means for detecting a four-wheel wheel speed based on a signal corresponding to a wheel speed of each of the four wheels of the vehicle and outputting a four-wheel wheel speed signal;
Electric power steering control abnormality monitoring means for detecting the presence or absence of abnormality of the electric power steering control computing means;
A function of calculating a first steering angle based on the steering angle signal, calculating a second steering angle based on the motor rotation angle signal, and calculating a third steering angle based on the four-wheel wheel speed signal. The electric power steering control abnormality monitoring means detects that the electric power steering control arithmetic means is not abnormal, and the first steering angle, the second steering angle, and the third steering angle A steering apparatus for a vehicle, comprising: a steering angle calculation unit that determines that the first steering angle is abnormal when the deviation is larger than a predetermined value.   The electric power steering control abnormality monitoring means detects no abnormality of the electric power steering control calculating means, and deviations between the first steering angle, the second steering angle, and the third steering angle are respectively detected. The deviation between the first steering angle and the third steering angle when the electric power steering control abnormality monitoring means detects an abnormality in the electric power steering control abnormality monitoring means when it is equal to or less than the predetermined value. 6. The vehicle steering apparatus according to claim 4, wherein when the value is equal to or less than the predetermined value, the first steering angle is set as a steering angle of the vehicle.   The electric power steering control abnormality monitoring means detects no abnormality of the electric power steering control calculating means, and deviations between the first steering angle, the second steering angle, and the third steering angle are respectively detected. The vehicle steering apparatus according to claim 4 or 5, wherein the third steering angle is set as a steering angle of the vehicle when the predetermined value is larger.   The vehicle steering apparatus according to any one of claims 1 to 7, wherein the electric power steering control calculation means and the steering angle calculation means are supplied with electric power from different power sources. .   The vehicle electric vehicle according to any one of claims 1 to 8, wherein the electric power steering control calculating means and the steering angle calculating means are provided on a separately grounded substrate. Steering device.   Steering angle calculation abnormality monitoring means for detecting whether or not the steering angle calculating means is abnormal, and the electric power steering control calculating means converts the steering absolute angle obtained by converting the motor rotation angle signal into the absolute angle signal of the steering shaft. And when the steering angle calculation abnormality monitoring device detects an abnormality in the steering angle calculation means, the steering absolute angle calculated by the electric power steering control calculation means is used as the steering angle of the vehicle. The vehicle steering apparatus according to claim 1, wherein the vehicle steering apparatus is a vehicle steering apparatus.   The electric power steering control calculation means has a function of outputting a signal indicating that the steering angle calculation means is abnormal when an abnormality of the steering angle calculation means is detected by the steering angle calculation abnormality monitoring means. The vehicle steering apparatus according to claim 10.   The steering angle calculating means outputs a signal indicating that the electric power steering control calculating means is abnormal when the electric power steering control abnormality monitoring means detects an abnormality of the electric power steering control calculating means. The vehicle steering apparatus according to claim 1, wherein the vehicle steering apparatus is provided.   The vehicle steering apparatus according to any one of claims 1 to 12, wherein the electric power steering control calculation means and the steering angle calculation means are housed in the same casing.

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